What percentage do I need for an A* in IGCSE Chemistry?

The grade threshold varies by exam series but is typically around 85-90% of the total marks. You need strong performance across all papers, not just one.

Is the A* boundary the same every year?

No. Cambridge adjusts grade boundaries each series based on paper difficulty. The threshold is published after results day. You should aim for a score well above the expected boundary to give yourself a margin.

What separates an A student from an A* student?

A* students make very few careless errors, can handle the hardest questions on the paper (especially multi-step calculations and extended responses), and write with the precision that mark schemes reward.

IGCSE Chemistry – Aiming for A*

What it takes to achieve an A* in Cambridge IGCSE Chemistry 0620. Strategy, exam technique, and the habits that separate top-grade students from the rest.

Published by IGCSEChemistry.com.my

Chemistry teaching team: K. S. Tan (15+ years teaching IGCSE Chemistry) and Ms Yash (10+ years teaching IGCSE Chemistry) and Ms Kartini (15+ years teaching IGCSE Chemistry).

Mapped to Cambridge IGCSE Chemistry 0620 (2026–2028). Last updated 2026-08-19.

An A* in IGCSE Chemistry is achievable, but it requires more than just knowing the content. You need near-complete accuracy on Paper 2, strong performance across every topic on Paper 4, and the ability to handle the most demanding questions confidently. This page covers what A* students do differently.

What the A* actually requires

The A* grade threshold for IGCSE Chemistry 0620 typically falls around 85-90% of the total marks across all papers. This means you cannot afford to give away marks on careless errors, incomplete working, or answers that are technically correct but imprecisely worded.

On Paper 2, you need 35+ out of 40 on the multiple choice. On Paper 4, you need consistently high marks across all question types, including the hardest questions at the end of the paper. On Paper 6, you need confident data interpretation and clear experimental descriptions.

What A* students do differently

They have no weak topics

An A or B student might be strong in most areas but weak in one or two. An A* student has addressed every weakness. This does not mean every topic is equally interesting or easy, but it does mean every topic has been revised and practised to exam standard.

Go through the syllabus topic by topic and honestly rate your confidence. Any topic you rate below “confident” needs work. Use the topics pages and past paper questions to close those gaps.

They master every calculation type

Calculation questions are where marks are most reliably available for strong students. An A* student can handle reacting masses, concentration calculations, titration calculations, percentage yield, empirical formula, bond energy calculations, and gas volume calculations without hesitation. The method is automatic, the arithmetic is accurate, and the working is clearly laid out.

Work through every calculation type in the calculations section. For A* preparation, accuracy matters more than speed. Get the method right, then get faster.

They write with precision

A* students do not waffle. They use the correct scientific terminology, they answer the question that was asked (not a related question), and they match their answer to the command word. When a question says “explain,” they give a reason. When it says “describe,” they say what happens without going into reasons.

For six-mark extended response questions, A* students plan their answer before writing. They include all the key points the mark scheme requires, in a logical order, using precise chemical vocabulary.

They learn from mark schemes

Reading the mark scheme after doing a past paper is the single most useful revision activity for an A* student. The mark scheme shows you exactly what the examiner is looking for. When your answer is close but not identical to the mark scheme, identify what is missing and adjust your answering style.

Over time, you start writing answers that read like mark schemes. This is not a coincidence; it is a skill developed through deliberate practice.

They do not lose marks carelessly

Careless marks are the enemy of the A*. Common sources include:

Not converting cm3 to dm3 in concentration calculations
Forgetting to balance an equation before using the mole ratio
Misreading a graph or table value
Omitting units from a calculated answer
Not showing the final step of working in a calculation

For every past paper you do, track how many marks you lost to careless errors versus genuine knowledge gaps. If careless errors are costing you more than 5% of the total, you have a technique problem to fix.

The revision plan for A*

Start earlier and be more systematic than average. By the time serious revision begins (four months before the exam), you should already be confident in most topics. Use the revision period to refine, not to learn from scratch.

Do at least 15 full past papers under timed conditions
Mark every paper against the mark scheme
Keep a log of recurring errors and check the log before each practice paper
Spend extra time on the question types that cost you the most marks

When to consider a tutor

If you are consistently scoring in the A range but cannot break through to A*, a specialist tutor can identify the specific habits or gaps holding you back. The difference between A and A* is often small but specific: it might be a recurring error in one calculation type, or a tendency to miss one mark point in extended responses. A tutor who focuses only on IGCSE Chemistry can spot these patterns and fix them efficiently.

Find out about how online IGCSE Chemistry classes work or book a trial lesson.

Read the full guide on how to get an A* in IGCSE Chemistry.

Studying this yourself? Tutoring arrangements are normally made by a parent or guardian. Message us for the details to share with them, or send them this page.